This invention relates generally to a flexible dip tube which depends from a manual dispenser and which extends into the liquid of a container to which the dispenser is mounted. The distal end of the tube tracks the bottom wall of the container and remains immersed in the liquid at low liquid levels even when spraying in upward and downward positions.
There are a wide variety of flexible dip tubes provided for liquid dispensers which are flexible for tracking the bottom wall of the container under the aforestated conditions. One such known dip tube is corrugated throughout its length or has the main portion of its length corrugated to provide flexibility, and which provides a weight in the form of a ball or the like at the distal end of the tube for maintaining that end immersed in the liquid when spraying from a nearly empty container in downward and upward attitudes of the sprayer. Such a dip tube is disadvantaged in several respects in that the increased diameter of the tube due to the large number of corrugations requires an unduly high number of pumping strokes to prime the pump given that air in the tube and in the pump chamber must be displaced with the liquid to achieve a full prime. Moreover, such a prior art tube requires an additional part in the form of a ball weight which adds to the cost of the overall dispenser package. Beside such a weight is difficult and time consuming to sub-assemble and yields mixed results.
Other prior art flexible dip tubes are known as having a limited corrugated section forming a bellows which thereby reduces the strokes-to-prime ratio to manageable levels but likewise requires some type of weight at its distal end in the form of a ball or other dense object for maintaining that end immersed in the liquid when dispensing from a nearly empty container in downward and upward attitudes of the sprayer. Again the cost and inconvenience of providing the weight is generally unacceptable in the industry of manual dispensers.
Still other known dip tubes have an integrally formed enlarged section which functions as a weight when the dip tube and the enlarged section accumulate liquid during priming. However, no integral flexible section is provided for such a known dip tube which is a drawback.
Also it is known that during the high speed assembly process practiced with modern day machinery, the standard dip tube of constant diameter between its ends is inserted into the tube retainer of the dispenser at either end of the tube. During the assembly process, a gripper grips an end section of the tube adjacent that end being inserted into the tube retainer. The length of the tube so gripped covers a tube length of about 1 inch or more for a 10 inch tube, for example.
This tube assembly process, while operating efficiently for dip tubes with constant diameter between their opposite ends, will not suffice for flexible dip tubes of the type known in the art. For example, since the flexible, and some end-weighted, dip tubes according to the prior art are not symmetrical about a central transverse axis, there is but one end, i.e., the proximate end, at which the dip tube can be coupled to the dip tube retainer of the dispenser or sprayer. The dip tubes must be first oriented with their proximate ends facing in a common direction, which requires an additional step in the assembly process and considerably slows the assembly process.